Most handheld remote control devices rely on infrared (IR) communication techniques and are typically battery-powered. Manufacturers have therefore engineered these remote controls to be as power-efficient as possible in order to prolong battery life. One primary way of prolonging battery life is to limit the power of the emitted IR signal by choosing low-power IR light emitting diodes (LEDs). Another way of prolonging battery life is to get the maximum benefit with the least amount of IR power by choosing IR light emitting diodes (LEDs) which have a very narrow angle of radiation. Thus, most of the IR power is directed along the optical axis of the LED, which provides line-of-sight transmission but only within a small angle. “Line-of-sight”, as used herein, means direct line-of-sight, that is, an unobstructed direct path with no reflections or obstructions. Also, many handheld remote control devices use both of these techniques to conserve power and maximize battery life.
This low power, focused, line-of-sight IR transmission scheme, however, is not without problems. IR communications are easily blocked by most objects, including furniture, a person who may be passing between the sensor and the controlled device, and even a wayward foot propped up on a pillow which happens to be between the remote control and the controlled device.
Users try to compensate for this problem by, for example, holding the remote control to one side or the other to send the signal around the intervening object while still aiming in the general direction of the controlled device. This approach, however, is often unsatisfactory because the narrow angle of radiation requires aiming with some degree of accuracy. Thus, two or even three attempts to perform a function, such as changing the channel, may be required.
Furthermore, although IR signals may be reflected off of certain surfaces, the power of the IR signal, while being adequate for line-of-sight transmission, is often inadequate for a signal which must be reflected or scattered off of another surface to avoid an intervening object and arrive at the controlled device. Thus, simply pointing the remote toward, for example, a wall in the hope that the reflected IR signal will have sufficient strength to affect the desired device is often not successful.
Also, some persons have large-screen TVs, elongated living rooms, and even in-home projection/theater systems. In these cases the available IR power may be inadequate to reliably traverse the distance between the remote control and the controlled device even if line-of-sight transmission is not a problem.
These problems are often exacerbated when a wireless touch-screen type IR remote control is used. This type of remote control requires the user to look at the screen on the remote control to be sure that the user is pressing on the correct screen area or icon while simultaneously pointing the remote control directly at the controlled device. This usually means holding the remote control in a low position so that it is easily viewed, which increases the likelihood that an intervening object will block the transmission. To avoid this problem, some persons have resorted to gymnastics such as holding the touch-screen device overhead so as to be above intervening objects, but with the screen pointing downward so that the user can look up to see the screen/icon and still be able to discern that the remote control is pointing toward the controlled device.
Furthermore, each controlled device is responsive only to IR commands sent by a compatible device. This usually means separate remote controls for each piece of equipment (e.g., a TV, a Blu-Ray Disc player, cable TV converter box, and an audio amplifier), and the sheer number of remote controls, and often their similarity in appearance, create confusion for many users. Also, each remote control needs its own batteries and must be pointed at its own controlled device: pointing the disc player remote control at the TV may not work if the disc player is not immediately adjacent to the TV. In order to reduce the number of remote controls which the user must have at the ready, there are “universal” remote controls which can control the multiple pieces of equipment. The user presses a button to select the desired device to be controlled, such as the disc player, and then presses the button to perform the desired function, such as pause, play, etc. These remote control devices also typically use low-power, narrow-bandwidth IR transmissions and are therefore subject to the same problems discussed above. For example, if the user wishes to control the disc player the user must remember to point the remote control at the disc player, not at the TV. The use of a universal remote control can also cause another problem when it is used to simultaneously turn on (or off) such multiple pieces of equipment that are not tightly grouped together. The All Power On/Off button is typically a power toggle command, so that a signal is sent to the controlled device instructing it to change states, that is, from the “on” state to the “off” (standby) state, or vice versa. As long as all devices receive the commands and they are all in sync (all on, or all off) then everything is fine. More common, however, is that pressing the All Power On/Off button often begins a frustrating experience for the user. For example, the user may come in after a hard day's work and, wanting to relax, sits down in front of the TV and presses the All Power On/Off button. Because of how the user is pointing the remote control, or because of the difference in distances between the remote control and the controlled devices, or because of different sensitivities of the controlled devices, the IR command signals sent by the universal remote control are only detected and acted upon by some of the devices so that, for example, the TV turns on, but the disc player does not. So, the user points the remote control more directly at the disc player and presses the All Power On/Off button again. Success? Not really. The disc player receives the power toggle command and turns on but, unfortunately, the TV set has also received the power toggle command, so it now obediently turns off. The user presses this button again, and the disc player and TV obediently reverse their states, the TV is on again, but the disc player is off again. In order to get the devices synchronized (both on, or both off), the user has to select the individual device on the remote control and then press the power button to get that particular device into the same state (on or off) as the other devices. This is usually a very frustrating experience, especially for users who are not tech-savvy and who do not understand that the power button is actually a power toggle button, and even for tech-savvy users who simply want to sit down and watch a movie with as little effort as possible. In situations where the various devices to be controlled are in widely separated locations, such as where the IR input for a home projection system or audio amplifier is in the back of the room but the disc player is in the front of the room, a standard IR universal remote control may be virtually useless.
Some prior art systems have attempted to address some of these problems by using a radio frequency (RF) remote control to transmit a control signal to an RF-to-IR converter box which has an RF receiver and LEDs therein. This converter box is then placed in front of the device to be controlled so that the LEDs on the box point directly into the IR sensor on the controlled device. This, however, has several disadvantages. For one, most persons would consider such an added box to be unsightly, at best. For another, there must be shelf space in front of the controlled device which is adequate for placement of the converter box. For yet another, the converter box requires an additional outlet. If one has four such converter boxes this would require four more outlets—in other words, most of the outlets in a typical power strip. And for another, each such converter box adds to the home power consumption. Although one box might only draw, for example, 15 watts, four such boxes would draw 60 watts, equivalent to leaving a 60-watt bulb burning day and night, thereby increasing electrical power consumption and increasing the loading on the home air conditioning system.
In an attempt to avoid the shelf space problem, some such systems have used converter boxes with the LEDs connected through an electrical cable to the converter box. This, however, leaves other problems unaddressed. Also, the LEDs and wires may still be considered unsightly by many, and a new problem has been created: how to reliably attach the LEDs to the front of the controlled device.
These problems are compounded if the user also wants to be able to occasionally use the original remote control with that device. In this situation the converter box or the wired LEDs would block the IR signal from the original remote control so they must be moved or removed in order to use the original remote control, and then replaced at a later time.